Goodyer IM, Croudace T, Dudbridge F, Ban M, Herbert J. Polymorphisms in BDNF (Val66Met) and 5-HTTLPR, morning cortisol and subsequent depression in at-risk adolescents.
Br J Psychiatry 2010;
197:365-71. [PMID:
21037213 PMCID:
PMC2966502 DOI:
10.1192/bjp.bp.110.077750]
[Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND
There is increasing evidence for genetic effects on the hypothalamic-pituitary axis system. More than one gene is likely to moderate corticoid-mediated activity.
AIMS
To investigate whether the brain-derived neurotrophic factor (BDNF) polymorphism (rs6265, Val66Met) is associated with morning waking salivary cortisol and moderates the corticoid-mediated risk for subsequent depressive episode onset independently of the known effects of 5-HTTLPR (the serotonin transporter gene promoter).
METHOD
High-risk adolescents (n = 401) were genotyped for Val66Met BDNF and 5-HTTLPR. Salivary samples were obtained on four consecutive school days within 1 h of waking. There were 365 (91%) remaining participants reassessed at 12 months for episodes of psychiatric disorder in the follow-up period. Of these, 357 (89%) had complete data for multivariate modelling.
RESULTS
There were 41 (11.2%) individuals who reported a new episode of clinical depression over the follow-up period. Increased risk for subsequent depression was found in carriers of the Val66Val genotype in BDNF with higher morning waking cortisol. This remained present when the known interaction between carriers of a short allele of 5-HTTLPR with higher morning salivary cortisol was taken into account.
CONCLUSIONS
Both BDNF and 5-HTTLPR genes show evidence of modifying the risk of a subsequent new depressive episode associated with elevated morning salivary cortisol. In adolescents morning salivary cortisol levels may constitute a biomarker for some forms of unipolar depression.
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